Support or stay member for parts of the electrode systems of electric discharge tubes



Feb. 17, 1959 K. A. BISTERFELD 7 SUPPORT OR STAY MEMBER FOR PARTS OF THEELECTRODE SYSTEMS OF ELECTRIC DISCHARGE TUBES Filed Dec; '7, 1953 GmssWOOL GLASS W001.

as W0 1- INVENTOR KARL BISTE HJFE 1.13

AGENT United States Patent SUPPORT OR STAY MEMBER FOR PARTS OF THEELECTRODE SYSTEMS OF ELECTRIC DESCHARGE TUBES Karl August Bisterfeld,Hamburg-Volksdorf, Germany, assiguor, by mesne assignments, to NorthAmerican Philips "Company, Inc., New York, N. Y., a corporation ofDelaware Application December 7, 1953, Serial No. 396,613

Claims priority, application Germany January 21, 1953 7 Claims. (Cl.174--167) In manufacturing electric discharge tubes, usually mica partsare used for supporting or holding the electrodes. Mica may besatisfactory from the point of view of vacuum but it exhibits a numberof limitations in other respects. The elasticity of the mica parts, forexample, is often insuflicient in mounting the electrodes. In addition,mica tends to splinter off with the result that the supporting orholding function which the mica parts are expected to perform is onlyinsufficiently fulfilled. In addition, mica is occasionally found to benot completely free of detrimental foreign matter.

Endeavours have been made to avoid the above-mentioned disadvantages bythe use of asbestos fabrics as supports or stay members for electrodesystems. However, asbestos has comparatively bad insulating propertiesand high dielectric losses. Furthermore, due to its tendency to befiuffy asbestos is not very suitable as a structural part in electricdischarge tubes, particularly since it can be degassed only withdifiiculty. The invention provides a solution enabling the disadvantagesdescribed to be avoided.

According to the invention a support or stay member for parts of theelectrode systems of electric discharge tube consists of a fabric ofquartz threads, glass wool or slag wool which is at least partly pastedwith cement.

The use of glass wool or slag wool ensures sutficient elasticity of thesupports or stay members. The said threads exhibit a smooth surface; dueto this and due to the length of the threads a resilient network isobtainable, the known support members made of the fibrous short stapleasbestos wool on the other hand having practically no rigidity.

In order to paste the fabric use may be made of silicon lacquer, siliconresin or a similar material. Such coatings of lacquers or resins cementthe fabric in a manner such that it is only gradually actuated byresilient reactive forces and ensures a satisfactory support when thecoats have been hardened.

The fabric itself may be manufactured in a variety of textures; that is,it may be dense or exhibit comparatively large apertures. Thus morevariety than in the case of the known asbestos fabric is made possible.

The cement may cover the whole fabric or it may only serve to paste thepoints at which the fabric and the system parts required to be supportedengage one another.

Similarly to what is well known in mice. discs the fabrics according tothe invention may be provided with radial projections or protuberancesat their outer periphery which may also be coated with silicon resinwhich has not yet been hardened, thus enabling the fabric to be smoothlyintroduced into the bulb of the discharge tube and ensuring that itengage the bulb wall satisfactorily. In addition, a support member thusprepared and introduced will stick to a greater or less extent to thebulb wall by means of its protuberances.

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in discharge tubes which are subjected to high temperatures it is alsopossible to provide the fabric according to the invention with a coatingmade of a ceramic suspension, a rim surrounding the prepared aperturesremaining uncovered, with the result that the thread-ends projectingbeyond the part covered with ceramic material enable the system parts tobe resiliently held. In order to fix the ceramic materials applied theycan be se cured by firing in a known manner.

The invention will now be described with reference to the accompanyingdrawing in which some embodiments thereof are shown by way of example.

Referring now to the figures, Fig. I shows a thin fine fabric made ofglass Wool, slag wool or quartz threads which may be impregnated withsilicon resin or silicon lacquer. In the punched aperture 1 theelectrode parts 3 required to be supported are held by a large number ofresilient thread ends.

The apertures acting to accommodate the system parts are not necessarilypunched, they may alternatively be formed by pressing a pointed mandrelthrough the fabric with the result that the electrode parts required tobe supported are engaged by threads which have been pushed aside andalso ensure these parts to be satisfactorily held.

In the embodiment shown in Fig. 2 the aperture 1a has been made by meansof a pointed mandrel.

Fig. 3 finally shows a disc-shaped support or stay member according tothe invention in which an aperture 1b has been made. A ceramicsuspension is applied to the fabric and secured by firing. The areaadjacent the aperture 1b is not covered by the ceramic coating.

What is claimed is:

1. In an evacuated device, an electrode system comprising at least oneelectrode portion and a support therefor, said support comprising arelatively stiff, self-supporting, at least partly cemented fabricconstituted of vitreous insulating flexible material, said fabric havingan aperture, said electrode portion engaging a portion of the fabricsurrounding said aperture.

2. An evacuated device as claimed in claim 1 wherein the vitreousmaterial is selected from the group consisting of quartz threads, glassWool and slag wool.

3. An evacuated device as claimed in claim 2 wherein the cement consistsof a silicon-containing substance.

4. In an evacuated device, an electrode system comprising at least oneelectrode portion and a support therefor, said support comprising arelatively stiff, self-supporting, at least partly silicon-cementedfabric constituted of a vitreous insulating material selected from thegroup consisting of quartz threads, glass wool and slag wool, saidfabric having a central aperture, said electrode portion engaging aportion of the fabric surrounding said aperture.

5. An evacuated device as set forth in claim 4 wherein the cement isdisposed along the portions of the fabric adjacent the aperture.

6. An evacuated device as claimed in claim 4 wherein the fabric ismounted on a ceramic member.

7. An evacuated device as claimed in claim 4 wherein the fabric isprovided with projections along its periphery.

References Cited in the file of this patent UNITED STATES PATENTS1,837,566 Mcllvaine Dec. 22, 1931 2,224,484 Morrow Dec. 10, 19402,626,223 Sattler Jan. 20, 1953

